Aircraft adapted for transporting cargo

ABSTRACT

The fuselage of an aircraft comprises a floor structure, a roof structure, a first lateral side structure, a second lateral side structure, and a middle structure. The floor structure, the roof structure, the first lateral side structure, and the second lateral side structure define a fuselage space between them. The middle structure spans at least part way between the floor structure and the roof structure, and runs between the first lateral side structure and the second lateral side structure such that the middle structure partitions the fuselage space into an occupant space and a cargo space. A seat for a pilot is disposed in the occupant space lateral to a portion of the middle structure and a portion of the cargo space.

FIELD OF THE INVENTION

The present invention relates generally to aircraft, and, moreparticularly, to aircraft specially adapted to carry cargo.

BACKGROUND OF THE INVENTION

The majority of light aircraft are configured with relatively smallcargo compartments located aft of the seating for the occupants. As aresult, these aircraft are not well suited for carrying relativelylarge, elongate items such as bicycles, motorcycles, snowmobiles, jetskis, and small boats. An issue frequently faced by pilots of theseaircraft is therefore what to do about transportation and recreationafter reaching a destination airport. Such an issue is of particularsignificance when accessing rugged backcountry airstrips where there maybe little or no infrastructure. While the aircraft and pilot are capableof reaching these locations, there may be little to do when gettingthere other than, perhaps, camping and hiking with relatively littlegear and supplies.

There have been several attempts to address this issue. Solutions haveincluded, for example, creating hybrid vehicles that are capable ofacting as both an aircraft and as an automobile. A modern example is the“Transition” created by TERRAFUGIA® (Woburn, Mass., USA). Nevertheless,these hybrid vehicles have not achieved significant adoption despitesubstantial efforts by their designers. In many cases, the compromisesrequired to combine an aircraft and an automobile into a single vehicleresult in a vehicle which is not particularly good at either function.These hybrid vehicles, moreover, are not typically well suited tooff-road use.

Other solutions have focused on reducing the size of the cargo, namely,by providing folding land and water vehicles such as folding bicyclesand canoes. Here again, however, the folding vehicles tend to becompromised in terms of strength and performance, and the solution doesnot lend itself easily to motorized land and water vehicles. At the sametime, even when folded, these bicycles and canoes are often still toolarge to easily fit in a small aircraft. Moreover, even when suchfolding vehicles can be loaded in a light aircraft, they frequentlyreduce the ability of that aircraft to carry passengers.

For the foregoing reasons, there is a need for light aircraft designsthat are readily capable of carrying relatively large cargo withelongate shapes such as bicycles, motorcycles, snowmobiles, jet skis,and small boats.

SUMMARY OF THE INVENTION

Embodiments of the present invention address the above-identified needsby providing aircraft designs with unique cargo carrying capabilities.

Aspects of the invention are directed to an aircraft with a fuselage.The fuselage comprises a floor structure, a roof structure, a firstlateral side structure, a second lateral side structure, and a middlestructure. The floor structure, the roof structure, the first lateralside structure, and the second lateral side structure define a fuselagespace between them. The middle structure spans at least part way betweenthe floor structure and the roof structure, and runs between the firstlateral side structure and the second lateral side structure such thatthe middle structure partitions the fuselage space into an occupantspace and a cargo space. The occupant space is disposed between thefirst lateral side structure and the middle structure, while the cargospace is disposed between the second lateral side structure and themiddle structure. A seat for a pilot is disposed in the occupant spacelateral to a portion of the middle structure and a portion of the cargospace.

Advantageously, aspects of the invention may be retrofittable ormodifiable to existing aircraft so as to provide those aircraft with thecapability to carry relatively large, elongate cargo. Weight of thecargo may be distributed close to and along the centerline of theaircraft so as to not adversely affect lateral/longitudinalcenter-of-gravity and controllability.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 shows a left perspective view of an aircraft in accordance with afirst illustrative embodiment of the invention;

FIG. 2 shows a right perspective view of the FIG. 1 aircraft;

FIG. 3 shows a partially broken right perspective view of the FIG. 1aircraft;

FIG. 4 shows a partially broken left perspective view of the FIG. 1aircraft with cargo;

FIG. 5 shows a right perspective view of the joined tubing forming thefuselage of the FIG. 1 aircraft;

FIG. 6 shows a left perspective view of the joined tubing forming thefuselage of the FIG. 1 aircraft;

FIG. 7 shows a top elevational view of the joined tubing forming thefuselage of the FIG. 1 aircraft;

FIG. 8 shows a bottom elevational view of the joined tubing forming thefuselage of the FIG. 1 aircraft;

FIG. 9 shows a right perspective view of the joined tubing forming thefuselage of the FIG. 1 aircraft with the first lateral side structurehighlighted;

FIG. 10 shows a right elevational view of the first lateral sidestructure of the FIG. 1 aircraft;

FIG. 11 shows a left perspective view of the joined tubing forming thefuselage of the FIG. 1 aircraft with the second lateral side structurehighlighted;

FIG. 12 shows a left elevational view of the second lateral sidestructure of the FIG. 1 aircraft;

FIG. 13 shows a left perspective view of the joined tubing forming thefuselage of the FIG. 1 aircraft with the middle structure highlighted;

FIG. 14 shows a left elevational view of the middle structure of theFIG. 1 aircraft;

FIG. 15 shows a right perspective view of floors and coverings in theFIG. 1 aircraft;

FIG. 16 shows a left perspective view of floors and coverings in theFIG. 1 aircraft;

FIG. 17 shows an exploded left perspective view of the doors associatedwith the second lateral side structure of the FIG. 1 aircraft;

FIG. 18 shows a left perspective view of pivoting structural members inthe FIG. 1 aircraft with the pivotal structural members pivoted out ofthe way; and

FIG. 19 shows a left perspective view of an aircraft in accordance witha second illustrative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with reference to illustrativeembodiments. For this reason, numerous modifications can be made tothese embodiments and the results will still come within the scope ofthe invention. No limitations with respect to the specific embodimentsdescribed herein are intended or should be inferred.

Moreover, while an aircraft has a myriad of components and systems, onlythose elements important to setting forth aspects of the invention aredescribed with any particularity herein. Nevertheless, one havingordinary skill in the relevant arts will recognize the additionalelements needed to make a viable aircraft. Reference is also made to thefollowing references, which are published by the Federal AviationAdministration of the U.S. Department of Transportation:

-   -   Pilot's Handbook of Aeronautical Knowledge (2008);    -   Aviation Maintenance Technician Handbook (2008);    -   Aviation Maintenance Technician Handbook—Airframe, Volumes 1 and        2 (2012); and    -   Aviation Maintenance Technician Handbook—Powerplant, Volumes 1        and 2 (2012).        Reference is further made to: D. J. Perry, Aircraft Structures,        Courier Corporation, 2013; and I. Moir et al., Aircraft Systems:        Mechanical, Electrical, and Avionics Subsystems Integration,        Third Edition, Wiley, 2008. All of these references are hereby        incorporated by reference herein.

Certain terms and phrases have particular meanings in the presentdescription and the appended claims. The term “aircraft” means any kindof machine capable of flying by gaining support from the air. The termtherefore encompasses, but is not limited to, fixed wing aircraft androtorcraft. The term “fuselage” means the main body of an aircraft. Afuselage may therefore contain spaces for occupants and cargo, flightinstruments and controls, and attachment points to other major aircraftcomponents (e.g., wings, tail, engine, landing gear). A first structureis “removably attached” to a second structure if the first structure maybe detached from, and reattached to, the second structure withoutpermanent alteration of any elements by destructive acts such ascutting, grinding, or breaking. Lastly, a “structural member” of anaircraft is a structure that provides strength and support to thataircraft. A structural member resists at least one of tension,compression, bending, shear, and torsion acting on the aircraft. In anaircraft, a structural member may include, as just some examples,longerons, tubes, struts, braces, stringers, ribs, bulkheads, frames,formers, skins, and the like.

The aircraft designs set forth herein will be described with referenceto directional terms such as “longitudinal,” “lateral,” “vertical,”“forward,” “aft,” “left,” and “right.” These directions are referencedto an aircraft oriented as if it were in level flight from the vantagepoint of a pilot sitting in a pilot's seat. The forward direction istowards the nose of the aircraft, while the aft direction is towards thetail of the aircraft. The longitudinal direction runs from nose to tail,and the lateral direction runs from side to side (e.g., from wingtip towingtip in a fixed wing aircraft). The vertical direction runsvertically through the aircraft perpendicular to the longitudinal andlateral directions.

FIGS. 1-4 show an aircraft 100 in accordance with an illustrativeembodiment of the invention. FIG. 1 shows a left perspective view; FIG.2 shows a right perspective view; and FIG. 3 shows a partially brokenright perspective view. FIG. 4 shows a partially broken left perspectiveview of the aircraft 100 with the addition of cargo. The aircraft 100comprises a fuselage 105, wings 110, an engine compartment and engine115, a propeller 120, a tail section 125, and a landing gear 130. In thepresent illustrative, non-limiting embodiment, the aircraft 100 appearssomewhat similar to a Piper PA-18 Super Cub, previously manufactured byPiper Aircraft (Vero Beach, Fla., USA). The aircraft 100 is widened incomparison to a PA-18, as indicated by an arrow 132 in FIG. 1.

As will be further detailed below, the aircraft 100 includes a middlestructure 135 that partitions the fuselage into an occupant space 140and a cargo space 145. The cargo space 145 runs longitudinally down theaircraft 100, starting at a forward end of the fuselage 105 (i.e., atthe firewall) and continuing for about two-thirds of the length of thefuselage 105. A seat for a pilot 150 and a seat for a passenger 155 arearranged in a tandem fashion in the occupant space 140. These seats 150,155 sit lateral to a portion of the middle structure 135 and a portionof the cargo space 145. Entry and egress from these seats 150, 155 isprovided by an occupant door 160. Access to the cargo space 145 isprovided by a forward cargo door 165 and an aft cargo door 170.

The cargo space 145 allows the aircraft 100 to carry relatively largecargo with elongate shapes. That is, the aircraft 100, and moregenerally, embodiments in accordance with aspects of the invention, arewell suited to carrying bicycles, motorcycles, snowmobiles, jet skis,and small boats. In FIG. 4, for example, a motorcycle 1000 is loadedinto the cargo space 145 of the aircraft 100. Because the cargo ispositioned close to and along the centerline of the aircraft 100, thecargo will not cause the center-of-gravity of the loaded aircraft 100 toshift significantly left/right or forward/aft. Beyond the added weightof the cargo, controllability of the aircraft 100 should therefore notbe significantly modified by the presence of the cargo.

In the illustrative aircraft 100, the structure of the fuselage 105 isof a truss design, meaning that it is primarily formed of joinedmetallic tubes (e.g., aluminum, steel) covered in aircraft fabric (e.g.,polyethylene terephthalate), although it is again emphasized that suchconstruction is non-limiting. Joining may be variously by welding,screwing, and bolting. FIGS. 5-14 show features of this constructionwith the aircraft fabric and other elements removed to just revealjoined tubing 175 of the fuselage 105. For purposes of describingaspects of the invention, the fuselage structure can be conceptuallyseparated into a floor structure 180, a roof structure 185, a firstlateral side structure 190 (in the present embodiment, forming the leftside of the fuselage 105), a second lateral side structure 195 (in thepresent embodiment, forming the right side of the fuselage 105), and themiddle structure 135. FIG. 5 shows a right perspective view of thejoined tubing 175 forming the fuselage 105, while FIG. 6 shows a leftperspective view, FIG. 7 shows a top elevational view, and FIG. 8 showsa bottom elevational view. FIG. 9 shows a right perspective view of thejoined tubing 175 forming the fuselage 105 with the first lateral sidestructure 190 highlighted, while FIG. 10 shows a right elevational viewof the first lateral side structure 190. Similarly, FIGS. 11 and 12 showleft perspective and elevational views, respectively, that highlight thejoined tubing 175 of the second lateral side structure 195, while FIGS.13 and 14 show right perspective and elevational views, respectively, ofthe joined tubing 175 forming the middle structure 135. The floorstructure 180, the roof structure 185, the first lateral side structure190, and the second lateral side structure 195 define a fuselage space200 between them.

As will be seen with reference to FIGS. 13 and 14, the middle structure135 runs down the fuselage 105 between the first lateral side structure190 and the second lateral side structure 195. In the presentembodiment, the forward approximate three quarters of the middlestructure 135 runs midway between the first and second lateral sidestructures 190, 195, while the remaining aft quarter of the middlestructure 135 angles towards the second lateral side structure 195 untilit ultimately merges therewith. A forward portion of the middlestructure 135 spans only part way from the floor structure 180 to theroof structure 185, while an aft portion of the middle structure 135spans all the way from the floor structure 180 to the roof structure185. The middle structure 135 thereby partitions the fuselage space 200into the occupant space 140 and the cargo space 145. The occupant space140 is disposed between the first lateral side structure 190 and themiddle structure 135. The cargo space 145 is disposed between the secondlateral side structure 195 and the middle structure 135.

In most aircraft, the structure of one lateral side closely replicatesthe structure of the other lateral side. That is not the case in theaircraft 100. Instead, in the present embodiment, some of the structuralelements that would normally be found in the second lateral sidestructure 195 are placed into the middle structure 135. The secondlateral side structure 195 is thereby made more conducive to the loadingand unloading of cargo into the cargo space 145.

A comparison of the joined tubing 175 of the first lateral sidestructure 190, the second lateral side structure 195, and the middlestructure 135 can be appreciated with reference to the elevational viewsin FIGS. 10, 12, and 14, respectively. Much of a truss design gets itsstrength from connecting tubes into triangular shapes (i.e., trusses).Comparison of FIG. 10 and FIG. 14 shows that several of the tubesforming the first lateral side structure 190 are directly replicated inthe middle structure 135. In contrast, comparison of FIGS. 10, 12, and14 demonstrates that the forward region of the second lateral sidestructure 195 is somewhat more sparse in construction compared to themiddle structure 135 and the first lateral side structure 190. That is,fewer joined tubes 175 are utilized in the second lateral side structure195 for the purpose of allowing cargo to be more easily loaded into thecargo space 145. In the present embodiment, the second lateral sidestructure 195 also includes joined tubing 175 that may be moved out ofthe way when loading and unloading the cargo space 145, which is furtherdetailed below.

The middle structure 135 therefore comprises structural members, meaningthat the joined tubing 175 forming the middle structure 135 providesstrength and support to the aircraft 100. That is, the middle structure135 resists at least one of tension, compression, bending, shear, andtorsion acting on the aircraft 100. The middle structure 135 is not amere non-structural partition solely intended to separate fuselage 105spaces as would, for example, a simple partition wall. Instead, themiddle structure 135 is taking on much of the role of a lateral sidestructure in a conventional aircraft in terms of providing strength tothe aircraft 100.

Floor surfaces and coverings within the fuselage space 200 are shown inFIGS. 15 and 16. FIG. 15 shows a right perspective view, while FIG. 16shows a left perspective view. The floor structure 180 defines anoccupant floor surface 205 that underlies the occupant space 140 and acargo floor surface 210 that underlies the cargo space 145. The floorsurfaces 205, 210 may be formed from, for example, metal, composites(e.g., fiberglass, carbon fiber), or wood (e.g., plywood). To helpaccommodate cargo, the cargo floor surface 210 is substantially flat fora majority of its length and spans about two-thirds of the total lengthof the fuselage 105 in the longitudinal direction. The cargo floorsurface 210 spans further aft in the aircraft 100 than does the occupantfloor surface 205.

Middle coverings 215 cover the middle structure 135. The middlecoverings 215 may be formed of a variety of materials such as aircraftfabric, metal, composites, and the like. An additional occupant spacepartition 217 spans between the middle structure 135 and the firstlateral side structure 190 and partitions the region occupied by thepilot and passenger from the aft portion of the fuselage 105.

Various attachment hardware may be added to the cargo space 145 to helpsecure cargo placed therein. The cargo floor surface 210 may, forexample, be fitted with tie down rings, eye bolts, hooks, or acombination thereof Alternatively or additionally, one or more tracks(e.g., aircraft L-tracks) may be attached to the cargo floor surface210. Likewise, the middle coverings 215 and the middle structure 135 maybe fitted with their own attachment hardware such as, but not limitedto, tie-down rings, eye bolts, bushings, and hooks. Suitable attachmenthardware for the cargo floor surface 210, the middle coverings 215, andthe middle structure 135 is available from, for example, US CargoControl (Urbana, Iowa, USA). With this hardware in place, cargo may beeasily secured in the cargo space 145 using straps, chains, and/or nets.

As stated above, the second lateral side structure 195 of the exemplaryaircraft 100 includes a forward cargo door 165 and an aft cargo door 170to aid in loading cargo into and out of the cargo space 145. FIG. 17shows an exploded left perspective view of these doors 165, 170. The aftcargo door 170 spans between the floor structure 180 and the roofstructure 185 and is removably mounted to the remainder of the aircraft100 via a plurality of quarter turn fasteners 220. These quarter turnfasteners 220 engage tubing at the periphery of the aft cargo door,including a door attachment tube 225 of the second lateral sidestructure 195. The quarter turn fasteners 220 allow the aft cargo door170 to be removed from the remainder of the aircraft 100 via a singlehand tool, such as a screwdriver. Suitable quarter turn fasteners areavailable from, for example, Specialty Fasteners & Components Ltd.(Devon, England).

The forward cargo door 165 likewise spans between the floor structure180 and the roof structure 185, but is fixated to the remainder of theaircraft 100 by a piano hinge 230. Three extendable/retractable doorpins 232 are tied to a door handle 235 via respective cables and engagecomplementary receiving holes 237 in the door attachment tube 225 of thesecond lateral side structure 195. The door handle 235 and the door pins232 thereby combine to allow the front cargo door to latch to the doorattachment tube 225. By simply actuating the door handle 235, theforward cargo door 165 may be swung open on the piano hinge 230 whileremaining attached to the remainder of the aircraft 100. The forwardcargo door 165 may also be temporarily removed from the aircraft 100 byremoving a hinge pin in the piano hinge 230.

To further aid in loading and unloading the aircraft 100, the doorattachment tube 225 as well as an adjacent tube 240 that is disposedbehind the aft cargo door 170 may be temporarily pivoted out of the way,which is illustrated in the left perspective view in FIG. 18. This isfacilitated by having these tubes 225, 240 be pivotally mounted to a toplongeron 245 of the of the second lateral side structure 195, whilesimultaneously being detachable from each other and a bottom longeron250 by removable pins 255. That is, the door attachment tube 225 and theadjacent tube 240 are pivotal structural members. Alternatively, thedoor attachment tube and the adjacent tube may be pivotally mounted tothe bottom longeron 250 and detachable from the top longeron 245.

So configured, relatively large cargo may be loaded into the cargo space145 by swinging the forward cargo door 165 open (or removing itentirely) and then removing the aft cargo door 170 utilizing ascrewdriver. Subsequently, the door attachment tube 225 and the adjacenttube 240 may be pivoted out of the way to provide unobstructed access tothe cargo space 145. Once the cargo is loaded and secured, the pivotaltubing 225, 240 and the doors 165, 170 may be secured back in place.Unloading the cargo may be accomplished in a similar manner.

It is preferred that the forward cargo door 165 and the aft cargo door170 be formed of a rigid material such as a metal (e.g., aluminum) or acomposite (e.g., fiber glass, carbon fiber). The attached doors 165, 170may thereby act as structural members for the aircraft 100 and provideadditional strength to the aircraft 100.

As indicated above, the cargo space 145 is well suited to carryingbicycles, motorcycles, snowmobiles, jet skis, and small boats (e.g.,kayaks, canoes). At the same time, the cargo space 145 may be used for amyriad of additional purposes. It may be utilized to carry, as just afew more examples, camping gear, hunting gear (and the resultantharvested game), and building supplies (e.g., full size timbers). Thecargo space 145 may also be utilized to carry drums of fuel and the like(e.g., 55 gallon drums). If fuel is carried, that fuel may even beplumbed into the aircraft's fuel system to give the aircraft 100additional range. In order to accommodate additional passengers, thecargo space 145 may be fitted with two or three additional passengerseats. The cargo space 145 may also be fitted with one or morestretchers for the transport of injured persons in a medevac role. Anurse sitting in the passenger seat 155 in the occupant space 140 may beable to attend to the injured persons across the middle structure 135.Lastly, as just a final example, the cargo space 145 could be utilizedto accommodate skydivers. The aircraft 100 may be fitted with wheel,skis, and floats, as desired.

In the aircraft 100, cargo is kept inside the fuselage 105 rather thanbeing strapped to the outside of the aircraft 100 or carried in externalpods, which may produce large amounts of drag. Strapping cargo to theoutside of an aircraft, while practiced in places such as Alaska, isconsidered dangerous and may be illegal.

Advantageously, the aircraft 100 may be formed in part utilizingcomponents from already existing aircraft 100 or, stated in the reverse,the fuselage 105 of the present aircraft 100 may be retrofitted into analready existing aircraft to provide that already existing aircraft withthe advantages of greater cargo carrying utility. For the presentillustrative aircraft 100, for example, wings, tails, landing gears, andengines may, for example, be sourced from existing Piper PA-18 Super Cubaircraft or similar, presently-manufactured, Cub-like designs from, forexample, CubCrafters (Yakima, Wash., USA) or American Legend AircraftCo. (Sulphur Springs, Tex., USA). In some cases, larger engines may bedesirable to aid in accommodating the extra weight of the cargo. Theselarger engines may be sourced from Lycoming Engines (Williamsport, Pa.,USA) or Continental Motors, Inc. (Mobile, Ala., USA).

It should again be emphasized that the above-described embodiments ofthe invention are intended to be illustrative only. Other embodimentscan use different types and arrangements of elements for implementingthe described functionality. These numerous alternative embodimentswithin the scope of the appended claims will be apparent to one skilledin the art.

For example, while the illustrative aircraft 100 detailed above was of atruss design, aspects of the invention may be applied to aircraft withdifferent types of structures (e.g., geodesic, monocoque,semi-monocoque, composite). FIG. 19 shows a left perspective view of amodified light, single-engine aircraft 300 with a semi-monocoque designthat utilizes riveted aluminum, in accordance with a second illustrativeembodiment of the invention. The modified aircraft 300 is similar to aCessna 185 manufactured by Cessna Aircraft Co. (Wichita, Kans., USA).The modified aircraft 300 includes a cargo space well suited forcarrying relatively large, elongate cargo, as well as a forward cargodoor 305 and an aft cargo door 310 suitable for loading such cargo.

All the features disclosed herein may be replaced by alternativefeatures serving the same, equivalent, or similar purposes, unlessexpressly stated otherwise. Thus, unless expressly stated otherwise,each feature disclosed is one example only of a generic series ofequivalent or similar features.

Any element in a claim that does not explicitly state “means for”performing a specified function or “step for” performing a specifiedfunction is not to be interpreted as a “means for” or “step for” clauseas specified in AIA 35 U.S.C. §112(f). In particular, the use of “stepof” in the claims herein is not intended to invoke the provisions of AIA35 U.S.C. §112(f).

What is claimed is:
 1. An aircraft with a fuselage, the fuselagecomprising: a floor structure; a roof structure; a first lateral sidestructure; a second lateral side structure, the floor structure, theroof structure, the first lateral side structure, and the second lateralside structure defining a fuselage space between them; and a middlestructure emanating from the floor structure and running between thefirst lateral side structure and the second lateral side structure suchthat the middle structure partitions the fuselage space into an occupantspace and a cargo space, the occupant space disposed between the firstlateral side structure and the middle structure, and the cargo spacedisposed between the second lateral side structure and the middlestructure; wherein the middle structure comprises a plurality ofstructural members that resist at least one of tension, compression,bending, shear, and torsion acting on the aircraft.
 2. The aircraft ofclaim 1, wherein the middle structure merges with the first lateral sidestructure or the second lateral side structure.
 3. The aircraft of claim1, wherein the fuselage is of a truss design.
 4. The aircraft of claim3, wherein the middle structure comprises joined tubing.
 5. The aircraftof claim 1, wherein: the first lateral side structure comprises aplurality of first structural members; and at least some of theplurality of first structural members are replicated in the plurality ofstructural members of the middle structure.
 6. The aircraft of claim 1,wherein a portion of the middle structure spans all the way between thefloor structure and roof structure.
 7. The aircraft of claim 1, wherein:a first portion of the middle structure spans all the way between thefloor structure and the roof structure; and a second portion of themiddle structure spans only part way between the floor structure and theroof structure.
 8. The aircraft of claim 1, wherein the second lateralside structure comprises a cargo door assembly.
 9. The aircraft of claim8, wherein the cargo door assembly spans between the floor structure andthe roof structure.
 10. The aircraft of claim 8, wherein the cargo doorassembly is removably mounted to a remainder of the aircraft.
 11. Theaircraft of claim 10, wherein the cargo door assembly is removablymounted to the remainder of the aircraft at least in part via aplurality of quarter turn fasteners.
 12. The aircraft of claim 10,wherein the cargo door assembly is removable from the remainder of theaircraft with only a single hand tool.
 13. The aircraft of claim 8,wherein: the second lateral side structure comprises a pivotalstructural member pivotally mounted to a different structural member ofthe second lateral side structure; and the cargo door assembly isremovably mounted to the pivotal structural member.
 14. The aircraft ofclaim 13, wherein the different structural member of the second lateralside structure comprises a longeron.
 15. The aircraft of claim 1,wherein the second lateral side structure comprises a hinged doorassembly, the hinged door assembly removably attached to a remainder ofthe aircraft.
 16. The aircraft of claim 15, wherein: the second lateralside structure comprises a pivotal structural member pivotally mountedto a different structural member of the second lateral side structure;and the hinged door assembly latches to the pivotal structural member.17. The aircraft of claim 1, further comprising seating for a pilotdisposed in the occupant space lateral to a portion of the middlestructure and a portion of the cargo space.
 18. The aircraft of claim 1,wherein the floor structure defines a cargo floor surface underlying thecargo space and spanning at least one-half of the fuselage in alongitudinal direction.
 19. The aircraft of claim 18, wherein the cargofloor surface is substantially flat for a majority of its length in thelongitudinal direction.
 20. The aircraft of claim 18, wherein: the floorstructure defines an occupant floor surface underlying the occupantspace; and the cargo floor surface spans further aft in the aircraftthan the occupant floor surface.